Semiconductor devices in these years have been required to integrate a comprehensive system to one package as following requests of downsizing and faster speed. However, it is difficult to integrate all the systems into one LSI chip due to increasing cost in view of the manufacturing process and yield. Accordingly, as means for downsizing and speeding up of semiconductor devices, a method of stacking a plurality of LSI chips has been employed.
In this case, means of communicating interactively between the stacked LSI chips is necessary. Therefore, as means of transferring information among a plurality of different LSI chips which are stacked, wireless communication using coupling between inductors formed on a silicon substrate has been studied as described in, for example, Japanese Patent Application Laid-Open Publication No. 2005-203657 (Patent Document 1) and U.S. Patent Application Publication No. 2007/0289772 (Patent Document 2).
FIGS. 13A and 13B are schematic diagrams each illustrating a schematic configuration of a conventional semiconductor device achieving communication by the coupling between inductors. FIG. 13B is a vertical cross-sectional view of the semiconductor device. FIG. 13B is a cross-sectional view taken along line A-A′ in FIG. 13A, and parts denoted by the same symbol are the same. In FIGS. 13A and 13B, the semiconductor device is formed of a transmitter LSI chip 100 and a receiver LSI chip 200.
As illustrated in FIG. 13B, the transmitter LSI chip 100 and the receiver LSI chip 200 are vertically stacked and fixed. On the transmitter LSI chip 100, transmitter circuits 110a to 110d are formed. On the other hand, on the receiver LSI chip 200, receiver circuits 210a to 210b are formed at respective positions corresponding to the transmitter circuits 110a to 110d when viewed in the stacking direction. Arrows in FIG. 13A illustrate relations of the corresponding positions.